Can form dense stands, preventing access to homes, water resources and pasture. On Madagascar, O. stricta has invaded land used for crop and pasture production, and has encroached on villages and roads, impeding human mobility (Larsson, 2004). Here, the cactus has had a negative impact on native grasses and herbs, and it is even affecting trees by inhibiting their growth and regeneration (Larsson, 2004). The small spines (known as glochids) on the fruit, when consumed by livestock, lodge in their gums, on their tongues, or in their gastrointestinal tracts, causing bacterial infections, while the hard seeds may cause rumen impaction, which can be fatal, and which often leads to excessive, enforced culling of affected animals (Ueckert et al., 1990). People who consume the fruits develop diarrhoea and may suffer from serious infections caused by the spines (Larsson, 2004). In Kenya, O. stricta infestations have resulted in the abandonment of farmlands.

Source:

Witt, Arne. 2017. Guide to the Naturalized and Invasive Plants of Southeast Asia. CAB International. Retrieved from http://www.cabi.org/cabebooks/ebook/20173158961 on 23 October 2018

Forms dense stands out-competing native species for light, space, nutrients and moisture, and its shade tolerance makes it able to thrive in forests. The thick rhizome mats also prevent the establishment of other species. Populations are now found on all islands in Hawaii (Smith, 1985). Its aggressive growth and shade tolerance means that it can form dense thickets in the understorey of open and closed-canopy Metrosideros polymorpha Gaud. (Myrtaceae) rainforests as well as in open habitats and forest edges around the Hawaii Volcanoes National Park (Anderson and Gardner, 1999). It threatens primary forest remnants in La Réunion and continuous expansion of large stands may endanger endemic lichens, vascular plants, molluscs and arthropods in the Azores. Infestations on Sao Miguel Island also threaten the Azores bullfinch. During rains, large infestations growing on steep slopes often become heavy with absorbed water and slip down slopes, contributing to erosion and gully formation.

Lantana forms dense impenetrable thickets reducing biodiversity and threatening the continued existence of a host of rare and endangered species. Turner and Downey (2010) identified 275 plant and 24 native animal species in Australia that are threatened by the presence of lantana. In crop production systems in Southeast Asia, it reduces yields and increases management costs for those growing durian, pineapple, banana and rubber (Waterhouse, 1993). It is also toxic to livestock with pastoral losses in Queensland in 1985, estimated to be A$ 7.7 million, as a result of 1,500 animal deaths, reductions in productivity, loss of pasture and control costs (van Oosterhout, 2004). In South Africa, lantana poisoning accounts for about 25% of all reported livestock poisoning by plants (Wells and Stirton, 1988). There have also been some recorded fatalities in people, after consumption of the green fruit. Lantana can also alter fire regimes, allowing fires to penetrate into forests and woodlands.

Source:

Witt, Arne. 2017. Guide to the Naturalized and Invasive Plants of Southeast Asia. CAB International. Retrieved from http://www.cabi.org/cabebooks/ebook/20173158961 on 23 October 2018

Leaves: Bright-green, twice-divided (10–20 cm long), 4–9 pairs of leaflet branchlets each with 12–30 pairs of small elongated leaflets (6–12 mm long and 1.5 mm wide) with pointed tips, leaves fold together at night or when touched.

Smothers other plants and prevents their natural regeneration. Dense stands also prevent or inhibit the movement of livestock and wildlife. In Nigeria, when M. diplotricha density reached 630,000 plants per hectare, cassava root yield, 12 months after planting, was reduced by 80% (Alabi et al., 2001). It readily invades orchards and rice paddies reducing yields and increasing management costs (Waterhouse, 1993). On cattle ranches in Papua New Guinea, up to US$ 130,000 is spent annually on chemical control (Kuniata, 1994). In Thailand, 22 swamp buffaloes died 18–36 hours after eating M. diplotricha (Tungtrakanpoung and Rhienpanish, 1992). Trials in Queensland, Australia, indicated toxicity to sheep, and a report from Flores, Indonesia, suggests that it is toxic to pigs (Parsons and Cuthbertson, 1992).

Source:

Witt, Arne. 2017. Guide to the Naturalized and Invasive Plants of Southeast Asia. CAB International. Retrieved from http://www.cabi.org/cabebooks/ebook/20173158961 on 23 October 2018